Process and apparatus for converting oils



Feb. 6, 1934. c. P. DUBBS PROCESS AND APPARATUS FOR CONVERTING OILS Oigi a1 Filed June 22, 1921 Cirbon Pflubb ma -(Mug,

Patented Feb. 6, 1934 PROCESS AND APPARATUS FOR CONVERTING OILS CarbonP. Dubbs, Wilmette, 111., assignor to Universal Oil Products Company,Chicago, 111., a corporation 01' South Dakota Application June 22, 1921,Serial No. 479,445 Renewed March 10, 1927 24 Claims. (01. 196-49) Thisinvention relates to improvements" in process and apparatus forconverting oil and refers more particularly to a process for treatingoils in successive stages of distillation.

5 Among the salient objects of the invention are to provide a process inwhich hydrocarbon oils of a relatively high boiling point are distilledin succeeding stages of distillation, each stage being maintained at areduced pressure to that immediately preceding it; to provide a processin which the distillate produced in each stage may be drawn off or rerunfor retreatment through the stage in which it was produced and a processin which the reflux condensate from each succeeding stage may bereturned and retreated in the higher pressure initial stage ofdistillation; to provide a process in which the temperatures at whichthe oil vapors in the respective stages are passed over to be condensedinto distillate, are regulated by controlling the supply of cool raw oilwhich isintroduced to the dephlegmating stages; to provide a process inwhich a mixture of the reflux condensate and raw oil from each stage israised to the pressure of the initial stage of distillation andintroduced thereto for retreatment; to provide a process in whichhydrocarbon oil may be converted to coke and oil distillate, there beingremoved during the conversion, distillates of relatively low boilingpoint and distillates adapted to be refined into marketable gasoline; toprovide an apparatus for carrying out the above-described process.

The single figure in the drawing is a diagram matic side elevationalview of the apparatus.

Referring in detail to the drawing, the apparatus is shown in threestages, although it is understood that any number of stages may be usedfor the conversion of the oil. The oil drawn from any convenient sourceflows through the raw oil pipe 1 and may be charged to the respectivestages through the secondary charging lines 2, 3 and 4 controlled byvalves 5, 6 and '7, respectively, these charging lines introducing theraw oil into the top of the dephlegmators 8, 9 and 10. The raw oil thusintroduced serves as a refluxing medium flowing in an opposed directionto the oil vapors which rise in the dephlegmators and refiuxes out thehigher boiling point fractions. Referring first to the initial stage,the raw oil introduced thereto with what condensate it may collect inthe dephlegmator, is drawn off through the line 11 regulated by a valve12 and passes to the heating tubes 13 through the line 14. The oil,after being heated to a cracking temperature in the heating tubes whichare mounted in the furnace 15, passes ferred through the line 23controlled by a valve 24 to a pump 25 where it may be charged back intothe top of the dephlegmator 8 through the line 26 regulated by ava1ve'2'7. By thus returning the distillate, it is again subjected tothe higher temperature of the vapors rising in the dephlegmator whichserve to redistill the liquid oil distillate returned from the receiver.The liquid oilwhich is not vaporized in the chamber 16, passes throughthe line 28 regulated by a reducing valve 29 and flows into the chamber30, where, due to the reduced pressure conditions, vapors are againreleased from the oil body. The vapors released in this chamber pass ofithrough the vapor line 31 through the refluxing or dephlegmating tower 9and are condensed in the water condenser 32 from which the distillate iscollected in the receiver 33. In this stage similarly to the initialstage, the distillate may be drawn off through the valve 34 or may bereturned through the line 35 controlled by a valve 36 and a pump 3'7 tothe de phlegmator 9 through the line 38 in which is in-= terposed thevalve 39.

By controlling the supply of oil introduced through the line 3, thetemperature of the vapors which pass over from the top of thedephlegmator .9 may be accurately controlled. The reflux from thisdephlegmating tower together with the raw oil which is introducedthrough the line 3 is drawn 011 from the bottom of the dephlegmatorthrough the pipe 40 controlled by a valve 41, through which it ischarged through the pump 41a into the line 14. This line is connecteddirectly with the heating tubes when the valve 42 is open, and when itis closed, the reflux from the second stage is directed through thevertical line 43 controlled by a valve 44 and is introduced into the topof the dephlegmator 8 of the first stage in quantities regulated by thevalve 44 in the line 43. In the same manner, the unvaporized oil fromthe second chamber 30 is passed through the line 45 controlled by asecond reducing valve 46 and flows into the chamber 47 where the reducedpressure permits further vaporization. The vapors released in this stagepass ofi through the line 48 to a dephlegmator 10 into the condenser 49and receiver 50. As before, the distillate collected therein may bedrawn ofi through the valve 51 or returned through the line 52 and pump53 to be charged into the top of the dephlegmator 10 through the line 54controlled by a valve 55. Similarly, the mixture of reflux and raw oilis drawn ofi from the bottom of the dephlegmator or refluxing columnthrough the line 56 regulated by a valve 57 and may be charged throughthe pump 58 through the line 59 in which is interposed the valve 60 intothe line 14 where it proceeds directly to the heating tubes to beretreated or if the valve 42 is closed, to the top of the first stagedephlegmator through the line 43.

The chambers 30 and 47 are mounted on furnaces 61 and 62, and all of thechambers and pipes are heavily insulated so that desired heat conditionsmay bemaintained throughout the system at all times. The reduction ofpressure betwen the succeeding stages will be governed wholly by thecharacter of the oil used and the distillate which it is desired toobtain. Each of the receivers is equipped with pressure relief valves 63and other appurtenances necessary for the regulation of operatingconditions in the respective stages. Pyrometers may be mounted in thetop of the dephlegmators and in the vaporizing chambers for controllingaccurately the temperature of the oil. Pressure gauges 64 in thereceivers serve to register at all times the pressure in the difierentstages. The oil' thus converted in succeeding stages of reduced pressuremay be relieved of substantially all of its lower boiling pointfractions and very completely cracked. The returning and redistilling ofthe distillate in the stage in which it is produced and furtherreturning the reflux to the initial stage of redistillation under thehigher temperature and pressure conditions produces a maximum degree ofcracking and conversion of the oil treated. The mixing of the raw oilwith the reflux in the separate stages promotes distillation therein andreduces materially the temperature and pressure conditions normally,necessary to distill these higher boiling point oils which pass over tothe second and third stage of distillation. In the last stage, thedistillation is practically completed and the final product remaining inthe vapor chamber will be coke or a very heavy carbonaceous material.

By converting gas oil at 300 pounds pressure in the first stage, 150pounds in the second stage and reducing the pressure to atmospheric inthe third stage, it is possible to obtain from 40 to 50% of 48 to 50degrees Baum gravity distillate in the first stage, and obtain 25% of 45degrees Baum gravity distillate in the second stage, while in the thirdstage, a somewhat heavier distillate is obtained, and the oil vaporizedto coke therein.

I claim as my invention:

1. A process of converting hydrocarbon oil, consisting in subjecting theoil to an initial conversion treatment by passing it through a unitcomprising a heating coil, vaporizing means and a dephlegmator, inmaintaining said initial unit under a superatmospheric pressure, inpassing unvaporized oils while in ahighly heated condition from thevaporizing means of said initial unit successively through succeedingunits, in reducing the pressure on the oil in each of said succeedingunits to vaporize substantial portions or the oil under the reducedpressures, in dephlegmating, condensing and collecting the vaporsevolved in each of the succeeding units, in returning the distillateproduced in each unit to the dephlegmating zone or that unit forredistillation therein, in returning the reflux condensate produced inthe several units to the heating coil of said initial unit forre-treatment.

2. A continuous process for treating hydrocarbon oils, consisting insubjecting the oil to a conversion treatment in an initial unit,comprising a heating coil, vaporizing means and a dephlegmator, inmaintaining a superatmospheric pressure on the oil undergoing treatmentin said initial unit, in continuously withdrawing unvaporized oil fromsaid initial unit and in passing it to the succeeding units wherein theoil is maintained under successively lower pressures to cause asubstantial vaporization thereof, in separately dephlegmating,condensing and collecting the vapors evolved in each of the succeedingunits, in controlling the temperature of the dephlegmating zone of eachunit by the introduction of raw oil and the pressure distillate producedin that unit thereto, and in passing the raw oil and reflux condensatefrom the dephlegmating zone of each unit to the inlet side of theheating coil of said initial unit.

3. A continuous process for treating hydrocarbon oils, consisting insubjecting the oil to conversion conditions in an initial unit,comprising a heating zone, a reacting zone and a dephlegmating zone, incontinuously passing unvaporized oil from the reacting zone of saidinitial unit to and through succeeding units, each succeeding unit beingmaintained under successively lower pressures to vaporize a substantialportion of the oil therein, in separately dephlegmating, condensing andcollecting the vapors evolved in each of said succeeding units, and inreturning pressure distillate produced-in each of said succeeding unitsto the dephlegmating zone of that unit to act as a dephlegmating mediumfor the vapors therein.

4. In an apparatus for converting oil, the combination with a series ofconnected distillation units, comprising an initial unit having aheating coil, a reacting chamber, dephlegmating and condensing means,successive units each comprising a reacting zone, and dephlegmating andcondensing means, of means for returning the distillate produced in eachunit to the dephlegmating zone of that unit for re-distillation, meansfor passing the reflux condensate from the dephlegmating zone of eachunit to the inlet side of the heating coil of said initial unit, andmeans for maintaining difierential pressures in the respective units.

5. A process for converting hydrocarbon oil, comprising passing the oilin a restricted stream through a heating coil disposed within a furnace, wherein it is raised to a cracking temperature, delivering theheated oil, while at a cracking temperature, to an enlarged reactionchamber, maintaining a superatmospheric pressure on the oil in said coiland reaction chamber, removing vapors evolved from the oil in saidreaction chamber, passing unvaporized oil from said reaction chamber toa secondary chamber, maintaining a lower pressure on the oil in saidsecondary chamber than is maintained in said reaction chamber, to effectvaporization of a substantial quantity of the unvaporized oil in saidsecondary chamber, removing vapors evolved from the oil in saidsecondary chamber, introducing said last mentioned vapors to afractionating column, passing charging oil for the process first inintimate contact with vapors in the vapor space of said fractionatingcolumn, thereafter passing the charging oil in heat interchange relationwith vapors removed from said reaction chamber, and subsequentlyadmitting the charging oil to said heating coil.

6. A process for converting hydrocarbon oil, comprising passing the oilin a restricted stream through a heating coil disposed within a furnace,wherein it is raised to a cracking temperature, delivering the heatedoil, while at a cracking temperature, to an enlarged reaction chamber,maintaining a superatmospheric pressure on the oil in said coil andreaction chamber, removing vapors evolved from the oil in said reactionchamber, passing unvaporized oil from said reaction chamber to asecondary chamber, maintaining a lower pressure on the oil in saidsecondary chamber than is maintained in said reaction chamber, to effectvaporization of a substantial quantity of the unvaporized oil in saidsecondary chamber, removing vapors evolved from the oil in saidsecondary chamber, introducing the same to a fractionating tower,passing charging oil for the process in physical contact with vaporsremoved from said secondary chamber in the vapor space of said tower andin physical contact with the vapors removed from said reaction chamber,and thereafter introducing the charging oil to the heating coil.

7. A process for converting hydrocarbon oil comprising passing the oilin a restricted stream through a heating coil disposed within a furnace,wherein it is raised to a cracking temperature, delivering the heatedoil while at a cracking temperature to an enlarged reaction chamber,maintaining a super-atmospheric pressure on the oil in both said coiland reaction chamber, removing vapors first evolved from the oil fromsaid reaction chamber, passing unvaporized oil from said reactionchamber to a secondary chamber, maintaining a lower pressure on the oilin said secondary chamber than is maintained in said reaction chambersuflicient to eifect vaporization of a substantial quantity of theunvaporized oil by its contained heat in said secondary chamber,removing vapors evolved from the oil in said secondary chamber,initially passing charging oil for the process in counter-current flowand in physical contact with the vapors last evolved from the oil,subsequently passing the charging oil together with such condensate asis separated from the vapors last evolved from the oil incounter-current flow and in physical contact with the vapors firstevolved from the oil, and thereafter delivering the charging oil andcondensate separated from the vapors to said heating coil.

8. In processes of cracking higher boiling hydrocarbon oils to producelower boiling hydrocarbon oils by distillation under pressure atcracking temperatures in which unvaporized oil is withdrawn during thepressure distillation and subjected to further vaporization by itsself-contained heat under a reduced pressure, the improvement whichcomprises passing the vapors separated from the oil withdrawn from thepressure distillation into a tower, introducing fresh oil directly intothe vapor space in this tower, so as to bring the fresh oil and vaporsinto direct and intimate contact therein, thereby subjecting the vaporsto condensation, passing the vapors from the pressure still into areflux tower and introducing admixed condensate and unvaporized freshoil from the first mentioned tower into direct contact with the vaporstherein, and returning reflux together with admixed unvaporized oil fromthe said reflux tower to the pressure distillation.

9. In processes of cracking higher boiling hydrocarbon oils to producelower boiling hydrocarbon oils by distillation under pressure atcracking temperatures in which unvaporized oil is withdrawn during thepressure distillation and subjected to further vaporization by itsself-contained heat under a reduced pressure, the improvement whichcomprises passing the vapors separated from the oil withdrawn from thepressure distillation into a tower, introducing fresh oil directly intothe vapor space in this tower so as to bring the fresh oil and vaporsinto direct and intimate contact therein, thereby subjecting the vaporsto condensation, passing the vapors from the pressure still into areflux tower and introducing admixed condensate and unvaporized freshoil from the first mentioned tower while still in a heated statetherefrom into direct contact with the vapors in the said reflux tower,and returning reflux together with admixed unvaporized oil introducedinto the said reflux tower to the pressure distillation.

10. In processes of cracking higher boiling hydrocarbon oils to producelower boiling hydrocarbon oils by distillation under pressure atcracking temperatures in which unvaporized oil is withdrawn during thepressure distillation and subjected to further vaporization by itsself-contained heat under a reduced pressure, the improvement whichcomprises passing the vapors separated from the oil withdrawn from thepressure distillation into a tower, introducing fresh oil directly intothe vapor space in this tower so as to bring the fresh oil and vaporsinto direct and intimate contact therein, thereby subjecting the vaporsto condensation, and supplying admixed condensate and unvaporized freshoil from this tower to the pressure distillation without substantialreduction in temperature.

11. In processes of cracking higher boiling hydrocarbon oils to producelower boiling hydrocarbon oils by distillation under pressureat crackingtemperatures in which unvaporized oil is Withdrawn from the pressuredistillation during operation and subjected to further vaporization byits self-contained heat through reduction in pressure, the improvementwhich comprises taking off vapors from the pressure distillation andcondensing them to form a pressure distillate, subjecting the vaporsseparated from the unvaporized oil withdrawn from the pressuredistillation to a fractionating operation, and controlling thefraotionating operation by supplying thereto portions of the finaldistillate product recovered from the vapors taken 01f from saidfractionating operation to permit taking off as vapors from thefractionating operation a fraction containing constituents whichcorrespond to the components of said distillate product.

12. In processes of cracking higher boiling hydrocarbon oils to producelower boiling hydrocarbon oils 'by distillation under pressure atcracking temperatures in which unvaporized oil is withdrawn from thepressure distillation during operation and subjected to furthervaporization by its self-contained heat through reduction in pressure,the improvement which comprises taking off vapors from the pressuredistillation and condensing them toform a pressure distillate,subjecting the vapors separated from the unvaporized oil withdrawn fromthe pressure distillation to a fractionating operation, facilitatingsaid fractionating operation by supplying thereto portions of the finaldistillate products recovered from vapors taken off from saidfractionating operation.

13. In processes of cracking higher boiling hydrocarbon oils to producelower boiling hydrocarbon oils by distillation under pressure atcracking temperatures in which unvaporized oil is withdrawn during thepressure distillation and subjected to further vaporization by itsself-contained heat under a reduced pressure, the improvement whichcomprises passing the vapors separated from the oil withdrawn from thepressure distillation into a tower, introducing fresh oil directly intothe vapor space in this tower,

so as to bring the fresh oil and vapors into direct and intimate contacttherein, thereby subjecting the vapors to condensation, passing thevapors from the pressure still into a reflux tower and introducingadmixed condensate and unvaporized fresh oil from the first mentionedtower into direct contact with the vapors therein, returning refluxtogether with admixed unvaporized oil from the said reflux tower to thepressure distillation, and returning portions of the distillate productsof the process to said towers.

14. In processes of cracking higher boiling hydrocarbon oils to producelower boiling hydrocarbon oils by distillation under pressure atcracking temperatures in which unvaporized oil is withdrawn during thepressure distillation and subjected to further vaporization by itsself-contained heat under a reduced pressure, the improvement whichcomprises passing the vapors separated from the oil withdrawn from thepressure distillation into a tower, introducing fresh oil directly intothe vapor space in this tower, so as to bring the fresh oil and vaporsinto direct and intimate contact therein, thereby subjecting the vaporstocondensation, passing the vapors from the pressure still into a refluxtower and introducing admixed condensate and unvaporized fresh oil fromthe first mentioned tower into direct contact with the vapors therein,returning reflux together with admixed unvaporized oil from the saidreflux tower to the pressure distillation, and returning portions of thedistillate product recovered from the vapors taken off from said firstmentioned tower, back to said first mentioned tower.

15. In processes of cracking higher boiling hydrocarbon oils to producelower boiling hydrocarbon oils by distillation under pressure atcracking temperatures in which unvaporized oil is withdrawn during thepressure distillation and subjected to further vaporization by itsself-con- Y tained heat under a reduced pressure, the improvement whichcomprises passing the vapors separated from the oil withdrawn from thepressure distillation into a tower, introducing fresh oil directly intothe vapor space in this tower so as to bring the fresh oil and vaporsinto direct and intimate contact therein, thereby subjecting the vaporsto condensation, supplying admixed condensate and unvaporized fresh oilfrom this tower to the pressure distillation without substantialreduction in temperature, and returning a portion of the distillateproducts recovered from vapors removed from said tower into said tower.

16. A process for cracking hydrocarbon oils, consisting in heating theoil to a conversion temperature while passing the oil in a continuouslyadvancing stream through a heating zone, in directing the highly heatedoil successively through a plurality of enlarged chambers seriallyconnected, in separately drawing off the vapors evolved in each of saidchambers, in subjecting the vapors to dephlegmating and condensingactions, in maintaining decreasing pressure conditions in each of thesuccessive chambers, in returning reflux condensate resulting from thedephlegmating action of the vapors issuing from the chamber maintainedunder the lowest pressure to act as a dephlegmating medium for thevapors issuing from a chamber maintained under a higher pressure, and inreturning the reflux condensate resulting from the dephlegmation of thevapors issuing from the chamber maintained at the highest pressure undera mechanically applied pressure to said stream.

17. A continuous process for cracking hydrocarbon oil, consisting inraising the oil to a cracking temperature, while flowing in a streamthrough a heating zone, in delivering the heated oil from said stream tothe first of a plurality of serially connected enlarged vapor chambers,in separately removing vapors evolved from the oil from each of saidchambers, in subjecting the vapors removed from the first to the last ofsaid series of chambers to dephlegmation under successively lowerpressure conditions, in utilizing the reflux condensate separated fromthe vapors evolved in one of said chambers of the series as adephlegmating medium for the vapors evolved in a preceding chamber ofthe series, and in returning the reflux condensate separated from thevapors evolved in the first chamber of the series to said stream forretreatment.

18. A hydrocarbon oil cracking process which comprises passing a streamof the oil through a heating zone and subjecting the same therein tocracking conditions of temperature and pressure, discharging the heatedoil into a vapor separating zone wherein a separation of vapors andunvaporized oil takes place, separately withdrawing vapors andunvaporized oil from said vapor separating zone, dephlegmating saidvapors thereby forming reflux condensate, returning said refluxcondensate directly to said heating zone, passing said unvaporized oilto a second vapor separating zone wherein a further separation of vaporsand unvaporized oil occurs, withdrawing vapors from said second vaporseparating zone and subjecting the same to dephlegmation thereby formingadditional reflux condensate, and utilizing said additional refluxcondensate as a dephlegmating medium in the dephlegmation of the vaporswithdrawn from the first mentioned vapor separating zone.

19. An oil cracking apparatus comprising a heating coil disposed withina furnace, a vapor separating chamber communicating with said coil, asecond vapor separating chamber connected to the first mentionedchamber, a first dephlegmator communicating with said first mentionedchamber and a second dephlegmator communicating with said secondchamber, and means for introducing reflux condensate from said seconddephlegmator to said first dephlegmator or for passing the same directlyto said coil.

20. An oil cracking apparatus comprising a heating coil disposed withina furnace, a vapor separating chamber communicating with said coil, asecond vapor separating chamber connected to the first mentionedchamber, a first dephlegmator communicating with said first mentionedchamber and a second dephlegmator communicating with said secondchamber, means for introducing charging oil into the upper portion ofsaid second dephlegmator, means for-removing liquid from the lowerportion of said second dephlegmator and for introducing the same to theupper portion of said first dephlegmator, and means for passing liquidfrom the lower portion of said first dephlegmator to said coil.

21. An oil cracking apparatus comprising a heating coil disposed withina furnace, a plurality of serially connected vapor separating chamberscommunicating with said coil, a separate dephlegmator connected to eachof said chambers, means for selectively introducing charging oil to theupper portion of the dephlegmators, and

means for passing liquid from the lower portion of each of saiddephlegmators to said coil.

22. An oil cracking apparatus comprising a heating coil disposed withina furnace, a vapor separating chamber communicating with said coil, asecond vapor separating chamber connected to the first mentionedchamber, a first dephlegmator communicating with said first mentionedchamber, and a second dephlegmator communicating with said secondchamber, means for introducing charging oil to the upper portion of saidsecond dephlegmator, and means for passing liquid from the lower portionof said second dephlegmator to said coil, means for introducing liquidfrom the lower portion of said second dephlegmator into the upperportion of said first dephlegmator, and means for passing liquid fromthe lower portion of said first dephlegmator to said coil.

23. An oil cracking apparatus comprising a heating coil disposed withina furnace, a plurality of serially connected vapor separating chamberscommunicating with said coil, a separate dephlegmator connected to eachof said chambers, means for selectively introducing charging oil to theupper portion of the dephlegmators, and means for passing liquid fromthe lower portion of each of said dephlegmators to said coil, and meansfor passing liquid from the lower portion of a dephlegmator connected toone of said chambers into the upper portion of the dephlegmatorconnected to the preceding chamber of the series.

24. An oil cracking apparatus comprising a heating coil disposed withina furnace, a vapor separating chamber communicating with said coil, asecond vapor separating chamber connected to the first mentionedchamber, a first dephlegmator communicating with said first mentionedchamber, and a second dephlegmator communicating with said secondchamber, means for introducing charging oil to the upper portion of saidsecond dephlegmator, means for passing liquid from the lower portion ofsaid second dephlegmator to the upper portion of said first dephlegmatoand means for passing liquid from the lower portion of said firstdephlegmator to said coil.

CARBON P. DUBBS.

